Milk line check valve



FIG. 1 is a perspective view taken from the top, front and one side of a milk line check valve showing my new design;

FIG. 2 is a perspective view taken from the bottom, rear and side opposite that shown in FIG. 1;

FIG. 3 is a side elevational view of the same;

FIG. 4 is an elevational view taken from the side opposite that shown in FIG. 3;

FIG. 5 is a top plan view of the same; and

FIG. 6 is a bottom plan view of the same. 

The ornamental design for a milk line check valve, as shown. 